Operating mechanism



June 28, 1966 T. PARRls, JR 3,257,856

OPERATING MECHANISM Filed July 10, 1964 2 Sheets-Sheet l PIEo E THOMAS PARE/5 JP.

June 28, 1966 T. PARRls, .JR 3,257,856

OPERATING MEGHANIsM Filed July 1o, 1964 2 sheets-sheet 2 INVENTOR.

THOMAS PARRIS JR;

United States Patent Office 3,257,856 OPERATING MECHANISM Thomas Parris, Jr., Milwaukee, Wis., assignor to Square D Company, Park Ridge, Ill., a corporation of Michigan Filed July 10, 1964, Ser. No. 381,738 8 Claims. (Cl. 741-107) The present invention relates to switch operating mechanisms and is more particularly concerned with a selfcontained operating mechanism which may be mounted in any one of aplurality of positions on a'housing for an electric limit switch for the purpose of transmitting motion from an external force to a switch within the interior of the limit switch housing.

The present invention is concerned with an improved operator for a limit switch which is characterized by its rugged construction, reliability of operation and simplicity of construction. The operator according to the present invention is adapted to be mounted in any one of a plurality of positions on an end of an enclosure for a limit' switch and includes a shaft which rotates about an axis parallel to the end of the enclosure and is maintained in either of two positions when the shaft is rotated by alternately applied forces from opposite directions from points outside the limit switch.

It is an object of the present invention to provide an improved self-contained operator for a limit switch which operator may be mounted in any one of a plurality of positions on an end of an enclosure which contains a switching unit of the limit switch and to provide cooperating bosses and recesses on the end of the enclosure and the housing7 for the operator so a rugged nonrotatable connection is provided between the operator and enclosure when the operator is mounted on the enclosure in any oneof a plurality of positions. In carrying out the foregoing, it is an object to provide the operator with a rotatable sha-ft which is maintained in either of two positions and rotates about an axis parallel to the end of the enclosure and has an operating end extending beyond the housing of the operator so an operating arm may be attached thereto to transmit forces for rotating the shaft in opposite directions.

A further object of the present invention is to provide an improved operator for a limit switch lwhich is selfcontained ina housing and to provide the housing and switch enclosure, whereon the operator is mounted, with cooperating bosses and recesses which are arranged so the housing may be immovably mounted in a plurality of positions on the switch enclosure and to lprovide the operator with a shaft .which is rotatably movable between two resiliently held 4positions and to nonrotatably mount a pair of identical members on the shaft in a manner so the members face in opposite directions, the members each being provided with stop surfaces which are arranged to engage a portion of the housing for limiting rotation of the shaft in opposite directions of rotation between two predetermined positions and camming surfaces which are engageable with plungers extending from the end of the enclosure, which plungers are arranged to transmit rotation of the shaft to actuate switch units within the enclosure in response to rotation of the shaft and members.

Another object of the present invention is to provide an operator for an electric limit switch which operator -has a housing which may be mounted on an end of an enclosure containing the switching unit of the limit switchandhas a rotatable shaft extending between oppositely extending bores on opposite walls of a cavity within the housing to the exterior of the housing so a pair of identical cam members which are nonrotatably mounted on predetermined positions.

A more specific object of the present invention is to provide an operator for an electric limit switch which is adapted to be mounted in any one of a plurality of positions on an end of an enclosure for the switch unit of the limit switch and to provide the operator with al shaft which is rotatable in a housing for the operator in response to forces applied to the shaft exteriorly of the housing to rotate the shaft in either of two directions, a pair of identical members which are nonrotatably mounted on the shaft at opposite ends of a cavity in said housing in a manner so like faces on the members face in opposite directions and like stop and camming surfaces on the members respectively are disposed in quadrature with each other so the rotation of the shaft will be limited to 90 between two predeterminedl positions when the stop surfaces on the members engage portions of the housing and a resilient means for yieldably maintaining the shaft in either of the two positions which includes a spring which surrounds the shaft and is positioned between the members to lurge a pair of spaced balls into engagement with inclined surfaces on surface portions of the members facing each other so a camming surface on one of the members may engage a camming surface on a plunger extending from the end'of the enclosure and actuate the switch -unit within the enclosure in response to movement of the shaft when the shaft is moved from one resiliently held predetermined position to the otherposition by an external force.

Further objects and features of the invention will be readily apparent to those skilled in the art from the specification and appended drawings illustrating certain preferred embodiments in which:

FIG. l is an elevational view of an operator according to the present invention as mounted on an enclosure which contains a switching unit of a limit switch.

FIG. 2 is a bottom plan view of the operator in F-IG. l taken generally along a line in FIG. 1 in the direction of the arrows 2 2.

FIG. 3 is a cross sectional View taken along `a line'.

3 3 in FIG. 2.

FIG. 4 is a plan view of the top surface of the enclosure in FIG. l taken along a line in the direction of the indicating arrows 4 4.

FIG. 5 is' a perspective view of a cam member asV used in the operator according to the present invention.

FIG. 6 is a perspective view of a plunger which is positioned in one of the openings in the top end of the enclosure as in FIG. 4.

FIG. 7 is a` cross-sectional view of the operator aci cording to the present invention taken along line 7 7 v unit associated with the enclosure.

Patented June 2S, 1966 ln the drawings, the numeral designates a limit switch which includes an enclosure' 22 and an operator 24. As the present invention is principally concerned with the details of the operator 24 which may be used with a varietyl of switching mechanisms within enclosures which are similar to the enclosure 22 providing the enclosure will accept the operator 24 and have mechanisms which will respond to actuation of the operator 24, therefore the switching mechanisms within the enclosure 22 are not shown in detail. The operator 24, however, is particularly suited -for use with the mechanisms in an enclosure 22 which is fully disclosed in an application for United States patent, Serial No. 372,854, `tiled June 5, 1964, which has been assigned by the inventors Rudolf H. Kiessling and Carl A. Schaefer to the assignee of the present invention.

ln the preferred form of the present invention the en closure 22 has an upper or top Wall 26 which is square in shape and is provided with a central opening 28 and four quadrate openings 39, 31, 32 and 33, all of which extend into the cavity 34 within the enclosure 22. The openings Sti-31 are located equidistantly from the center of the opening 28 at the corners of an imaginary square which has its diagonals passing through the center of the opening 28.

Centrally located on the top wall 26 is a raised circular boss 35 which is centered at the center of the opening 28 and has a diameter sufficient to expose a flat surface 36 of the top wall 26 between the periphery of the boss 35 and the raised ribs 37 which extend upwardly from the four side edges of the top wall 26.

Extending upwardly from each of the four corners of the top wall 26 and projecting beyond the top surface of the ribs 37 is a raised boss-like portion 38. Each of the bosses 38 are identical and are generally square shaped and have a threaded bore 39 downwardly extending from the center of its top surface. Each of the bosses 38 are provided with an arcuate side wall 40 having a curvature defined by an arc centered in the center of the opening 28 to expose the surface 36 of the top wall 26 between each of the bosses 38 and the periphery of the circular boss 35.

Extending downwardly from the top surface of the circular boss 35 is an irregularly shaped recess 41 which is generally square in shape. For purposes of description, as shown in FIG. 4, the recess 41 will be said to have vertical wall portions 42 which constitute the remaining portions of an imaginary square recess which has its diagonals intersecting at the center of the opening 28 and its sides tangent to the portions of the openings 30-33 remote from the center of the opening 28. For further purposes of description, the recess 41 may be described as having a rectangular recess 43 at each of its four corners. As each of the recesses 43 are identical and face in opposite directions at the opposite diagonal corners of the recess 41, only the recess 43 in the lower left corner of FIG. 4 will be supplied with identification numerals. The recess 43 has walls 44 and 45 which intersect at right angles to provide corners 46. Each of the corners 46 of all of the recesses 41 are equidistantly spaced from the periphery of the boss 35. The recess 43 also has portions of walls 47 and 48 which are arranged so the center of an imaginary diagonal of the recess 43 does not coincide with the center of the openings 30-33. To accomplish the foregoing, the walls 44 and 48 are equidistantly spaced on opposite sides of the horizontal axis through the opening 33 while the walls and 47 are arranged so the wall 45 is at a greater distance from the vertical axis through the opening 33 than the wall 47.

Movably guided by the opening 28 `is a slider 51. The

slider 51 has a portion 52 received and guided in the opening 2S and a portion 53 positioned in the cavity 34 in engagement with a switch actuator 50. The portion 4 53 is sized to have front face portions thereof aligned with all of the openings 30-33.

Each of the openings 30-33 are arranged to receive a shank of a headed plunger which will be designated by a numeral Btl-33 and a suffix p which indicates the particular opening 36-33 wherein the plunger is installed. The designation 36p indicates the plunger in the opening 30, 31p indicates the plunger in the opening 31, etc.

The shank portion of the plungers 30p-33p are in engagement with the front face of the slider 51. Thus when any of the plungers 30p-33p are moved toward the cavity 34, the slider 51 will be moved. The actuator 5t) normally urges the slider 51 and the plungers 36p-33p toward the top wall 26. Thus when any of the plungers 30p-33p cause the slider 51 to move, the actuator 5l) will be moved to actuate the switch 49.

As was previously set forth, a plunger 3ilp-33p is receivable in any of the openings 30-33. lEach of the plungers has a shank portion 54 and a head portion 55. The shank portion 54 is received in the openings 30-33 which act as guides for reciprocal movement of the plunger 30p-33p. The head portions 55 of the respective plungers are received in the recesses 43 which are arranged so the plungers 30p-33p are oriented in a predetermined manner and are movable in the recesses 43. This is accomplished by locating the head portion 55 on the shank portion 54 so the side walls 56 and 57 on the head portion will be juxtaposed to the walls 44 and 48 of the recess 43 and the end walls 58 and 59 will be respectively juxtaposed to the end walls 45 and 47. Each of the head portions have an upper or top surface which is shaped to provide an upstanding wall which has an inclined camming surface 61 and an inclined clearance surface 62 which are joined at an apex 63. The surfaces 61 and 62 and the apex 63 are arranged on the wall 60 so the camming surface 61 extends from the wall 48 toward the wall 44 and the clearance surface 62 extends from the apex 63 toward the wall 44 in each of the recesses 43. Additionally, the top surface of each head portion 55 is provided with portions 64 and 65 provided as inclined surfaces which extend downwardly from the wall 60 to provide clearance for an operator when the plungers are in an inactive position, as will be hereinafter described.

The external operator mechanism 24 according to the present invention is provided with an external housing 66 which has a square shaped bottom surface 67 complementary in shape and size to the top wall 26 of the enclosure 22. The complementary shape of the surface 67 is accomplished by providing a recess 68 in each of the corners of the surface 67 which are complementary in size and shape with the bosses 38.

Further, the bottom surface is provided with a central circular opening 69. The opening 69 is centered in the square shaped bottom surface 67 and extends into an internal cavity 70 within the housing 66. The opening 69 has a diameter slightly larger than the diameter of the circular boss 35 and thus together with the recesses 68 effectively provides a raised rib 71 adjacent each of the corners and a raised boss 72 between the adjacent recesses 68. The ribs 71 and the bosses 72 are arranged to compress a sealing gasket, not shown, into sealing engagement with the surfaces 36 of the top wall 26 when the operator mechanism 24 is secured to the top wall 26.

The securement of the operator 24 to the enclosure 22 is accomplished by screws, not specifically shown, which extend through openings 75 in the recess 68 which are aligned with the threaded bores 39 so the screws may be tightened in the bores 39.

The housing 66 has an externally projecting hub 76 projecting from one side. The hub 76 has a bore 77 extending from a flat end 78 of the hub 77 into the cavity 70. The bore 77 is axially aligned with a bore 79 which extends from the cavity 70 partly into the side wall of the housing 66 opposite to the wall wherein the bore 77 is formed. The bores 77 and 79 provide bearing supports for a shaft 80 which has one end journalled in the bore 79 and its other end extending through the bore 77 external of the housing 66. If desired, the shaft 80 may be provided with a flange 81 which engages the end wall 78. Further if desired, the external end of the shaft 80 may be knurled to provide a means for nonro'tatably securing an external operator, such as an operator arm 83.

Positioned on the shaft 80 at opposite ends of the cavity 70 are a pair of identical cam members 84 and 85 which are arranged on the shaft 80 sotheir respective identical surfaces face in opposite directions. As each of the members 84 and 85 have identical configurations, only the specific details of the cam member 84 will be described, with the parts thereof indicated by an alphabetical suix, it being understood that a similar suffix applied to the cam member 85 will indicate a corresponding part on the member 85.

The cam member 84 has a front surface 84a and a rear surface 84b and a centrally located opening 84C extending between the front surface 84a and the rear surface 84b. The opening 84C receives the shaft 80 to thereby mount the members 84 and 85 in the shaft 80. The rear surface 84b, which is generally fiat, has a raised boss 84d formed thereon which has a groove 84e therein. The groove 84e extends in opposite directions along a' diameter from the center of opening 84C so a suitable pin 86, which'is seated in the groove 84e and extending through an openingin the shaft 80, may nonrotatably secure the member 84 in a predetermined angular position on the shaft 80 and axially position the shaft 80 within housing 66.

The front surface 84a of cam member 84 has a pair of straight ridges 84f and 84g extending in opposite directions along an axis defined by a diameter of the opening 84e which is preferably perpendicular to the groove 84e. The front surface 84a is provided with a pair of bosses 84h and 84]' which extend in opposite directions along an axis defined by a diameter of the opening 84C which is perpendicular to the axis of the ridges 84j and 84g. The bosses 84h and 84]' each have a top surface parallel with the rear surface 84b and together with the ridges 84f and 84g divide the front surface 84a into sloping surfaces 84k, 84m, 8411 and 84p. The surfaces 84k and 84m slope downwardly as flat surfaces from the ridge 84]c toward the periphery of the member 84 and similarly, the surfaces 84n and 84p slope downwardly as flat surfaces from the ridge 84g toward the periphery of the member 84. The boss 84h provides a raised division between the surfaces 84k and 84p which lie in a common sloping plane and the boss 84]' provides a raised division between the surfaces 84m and 8-4n which also lie in a common sloping plane. The cam member 84 has peripheral walls, as will be now described, which extend perpendicular to the rear surface 84b.

' The peripheral wall at the end of boss 84]' remote from the opening 84e is rounded to provide a curved portion 84]', which is defined by an arc which has a radius extending from the center of the opening 84e. The curved portion 84r extends in opposite directions to straight stop surfaces 84s and 8-4t which are formed tangent to the curved portion 84r and extend at a 45 angle to the axis of the bosses 84h and 84]. The stop surfaces 84s and 84! are therefore perpendicular to each other and are separated by the curved portion 84r with the stop surface 84s extending between the boss 84]' and the ridge 8-4f and .the stop surface 84t extending between the boss 84]' and the ridge 84g.

The peripheral wall atthe end of the boss 84h remote from the opening 84C is also rounded to provide a curved portion 84u which is defined by an arc having a radius slightly smaller than the radius which defined the curved portion 84r and which radius also extends 'from the center of the opening 84C. Extending Atangentially to the 'curved portion 84u from' the boss 84h toward the ridge 84f is a straight wall portion 84V which is disposed at 45 to the axis of the bosses 84h and 84]'. For purposes of clearance, a Iportion 84W is removed at the area where the straight flat wall 84V and the stop surface 84s intersect. Extending between the ridge 84g and the boss 84h is a curved dwell or cam surface 84x which is defined by an arc which has a radius greater than the radius which defined the curved surface 841' and also extending from the center of the opening 84C. face 84x will be at a greater distance from the center of the opening 84C than the curved surface 84u. The surfaces 84x and 84u are interconnected by a suitably curved portion 84). be provided with a raised rib 84z which is formed to generally follow the contours of the portions 84x and 84y and which has its upper surface extending above the sloping surface 84p so as to be coplanar with the top surfaces of the bosses 84h and 84j and the ridges 84f and 84g.

As shown in FIGS. 2, 7 and 8, the cam members 84 and 85 are positioned by the lpins 86 on shaft 80 so the cam members 84 and 85 are at opposite ends of the cavity with curved surfaces 84u and 85u of the cam members' 84 and 85 both generally facing toward the bottom surface 67. Also while not specifically shown, the pins 86 which secure the cam members 84 and 85 to the shaft are arranged to be in a common plane passing through the axis of the shaft 80 and are located so the rear surfaces 84b and 85h are spaced from the end Walls of the cavity 70. For purposesof description, the cam member 84 will be said to be positioned remote from the end of the housing whereat the hub 76 is located.

The angular relationship of the cams 84 and 85 on the shaft 84) is most clearly seen in FIGS. 7 and 8. The material of the housing 66 which provides the cavity 70 is arranged to provide a stop surface 87 at the end of the cavity 70 whereat the bore 77 is located and a stop surface 88 at the end of the cavity 70 from which bore 79 extends. The stop surfaces 87 and 88 each extend from` the top wall of the cavity 70 toward the bottom surface 67 a distance from the axis of bores 77 and 79 which is approximately equal to the radius which formed the rounded surfaces 841 and r on the cam members 84 and 85 so the stop surfaces 87 and 88 are respectively engaged bythe stop surfaces on the respective cam members 84 and 85, as will now be described.

When the cam members 84 and 85 are positioned by the pins 86 on the shaft 80 to face in opposite directions, it will be seen from FIGS. 7 and 8 that because the bosses 84h and 84]' and the grooves 84e extend along the same diameter through the opening 84C, the corresponding parts on the cam members 84 and 85-Will be on opposite sides of a center line 89 through the bosses 84h and 84j and the groove 84e.` Thus the surfaces 85x and 85t on the cam member 85 Will be on the same side of center line 89 as are the surfaces 84v and 84s on the cam member 84. Similarly, the surfaces 85V and 85s on the cam member 85 will be on the same side of the center line 89 as are the surfaces 84x and 84! on the cam member 84. Also it will be seen that the stop surface 85s on the cam member 85 is in engagement with the stop surface 88 to prevent rotation of the cam member 85 and the shaft 80 in a clockwise direction while the stop surface 841? on the cam member 84 engages the stop surface 8-7 to also prevent clockwise rotation of the cam member 84 and the shaft 80. It will also be noted that the carn surface 85x, is extended toward the bottom surface 67 while the surface 84x is in a retracted position from the bottom surface 67 when the shaft 80 is positioned, as in FIGS. 7 and 8. The cam members 84and 85 are releasably held in the position shown in FIGS. 7 and 8 by a resilient means which will be later described. While the stop surfaces 85s and 84t are arranged to prevent clockwise rotation of the cam members 85 and 84,`

it is apparent that because the rounded surfaces 85r and 84r are tangent to the stop surfaces 85s`and 841 and be- Thus the cam sur- If desired, the portions 84x and 84y may cause the stop surfaces 88 and 87 and the rounded surfaces 8-51 and S41- are equidistant from the center of the opening 84C and the shaft 80, the shaft S0 may be rotated counterclockwise 90 to a second position whereat the stop surface 851. on the cam member 85 and the stop surface 84s on the cam member 84 respectively engage the stop surfaces 8S and 87. The cam members 85 and 84 and the shaft S0 will be maintained at the second position by the resilient means. When the parts are thus positioned, the cam surface V84,1: is extended toward the bottom surface 67 while the surface 85x will be in a rctracted position relative to the bottom surface 67.

Also it will be seen that when the cam surfaces 85x an-d 84x are in the extended position they are disposed on opposite sides of the vertical centerline 89 through the shaft 80 in FIGS. 7 and 8 and that the cam members S5 and 84 and the sha-ft S0 may be rotated clockwise from the second position to the rst position so the cam members 85 and S4 are positioned as shown in FIGS. 7 and 8.

Further it will be seen that as the cam surfaces 84x and 85x are moved from their retracted positions toward their extended positions, the rounded curved portions 84y and Sy on the respective cam members 84 and 85 will rst pass through the vertical centerline in FIGS, 7 and 8. The rounded curved portions 8432 and SSy act as transitional surfaces between the surfaces 84V and SSv and the cam surfaces 84x and 85x on the respective cam members 84 and 85.

The resilient means which maintainsA the shaft 80 and the cam members 84 and 85 in either of the two positions just described includes a pair of ball retainers 90 Y and 91, a compression spring 92, a pair of washers 93 and 94 and four balls which will be later designated. The ball retainers'90 and 91 are each identical and are respectively positioned by the walls of the housing 66 within cavity 70 adjacent the cams 84 and 85, as in FIG. 3. Each of the ball retainers 90 and 91 is provided with a central open-ing which receives the shaft with clearance and a pair of openings equidistantly spaced on opposite sides of the central opening on centers located on a center line which is parallel to the bottom surface 67. Each of the pair of openings has a ball 95 positioned therein. The balls are urged into engagement with the front faces 84a and 85a of the cam members 84 and 85 by the washers 94 and 93 and the spring 92. The spring 92, which -is of the compression type, surrounds the portion of the shaft 80 between the ball retainers and 91 and constantly urges the Washer 93 toward the retainer 90 and the washer 94 toward the retainer 91. The washers 93 and 94 each have a central opening to receive the shaft 80 with clearance and other portions which are lin constant engagement with the balls in the pair of openings in the retainers 90 and 91 `so as to constantly urge the balls 95 into engagement with the surfaces 84a and 85a.

When the cams 84 and 85 are positioned as in FIG. 8, the ball 95 to the left of a vertical centerline will be in engagement with the sloping surface 85p while the ball to the right of the vertical centerline will be pressed into engagement with the sloping surface 85m. The d-irection of the slope of surfaces 85p and 85m causes the balls to respectively urge the cam member 85 in a clockwise direction of rotation to the rst position wherein the stop surface 85t engages the stop surface S7. When the parts are thus positioned, a ball 95 will be positioned intermediate the ridge 851 and the bass 85j on the sloping surface 85m and a ball 95 will be positioned intermediate the ridge 85g and the bass 85h on the sloping surface 85p. In view of the foregoing explanation it is believed it will be apparent that when the shaft 80 is positioned as in FIG. 8,` a ball Will be in engagement with the sloping surfaces 8411 and 34k to constantly urge the cam member 84 in a clockwise direction of rotation.

When an external force is applied to the shaft 80 and the cam members 84 and 85 to cause a counterclockwise rotation in FIG. 8 from the first position shown, the sloping surfaces 85m and 85p will cause the balls 95 to ride upwardly toward the ridges 85f and 85g on the cam member S5. As the balls 95 move along the surfaces 84m and 84p, the balls 95 through the washer 93 will compress the spring 92. lt will be seen that after the shaft S0 and the cam member 85 has been rotated through an angle of 45, the balls 95 will pass over the ridges 85)c and 85g and `into engagement with the sloping surfaces 85k and 8511 so the spring 92 through the Washer 93 causes the balls 95 to move downwardly on the sloping surfaces 85k and 8511 causing the cam member 85 to continue its rotation an additional 45 even though the external force which caused the initial rotation is removed after the balls pass over the ridges 85)c and 85g. The counterclockwise rotation of the cam member 85 ceases when stop surface 85s engages the stopy surface 87 andthe balls 95 come to rest in positions on the surfaces SSk and 8511 which are adjacent the bosses 85h and 85j, respectively.

Similarly, when the external force on the shaft 80 which caused the counterclockwise rotation of cam member S5 is applied, the cam member 84 will rotate counterclockwise from the rst position. When cam member 84 rotates from the first position, the sloping surfaces 84k and 84h will cause the balls 95 to ride upwardly toward the ridges 84f and 84g on the cam member 84. As the balls 95 move along the surfaces 34k and 8411, the balls 95 throughv the washer 94 will compress the spring 92. It will be seen that after shaft 80 and the cam member 84 thas been rotated through an angle of 45 the balls 95 will pass over the ridges 84f and 84g and into engagement with the sloping surfaces 84m and 84p so the spring 92 through the washer 94 causes the balls 95 to move downwardly on the sloping surfaces 84m and 84p causing the cam member 84 to continue its rotation an additional 45.even though the external force which causes the initial rotation is removed after the balls pass over the ridges 84f and 84g. The counterclockwise rotation of cam member S4 ceases when the stop surface 84t engages the stop surface 88 and the balls 95 come to rest in positions on the surfaces 84m and 84p which are adjacent the bosses 84j and 84h, respectively.

A preferred form of the external operator 83, as shown in FIG. l, includes a hub portion 96 which may be secured to the knurled end of the shaft 80 extending external to the housing 66 and a pair of arms 97 and 98 which extend from the hub portion 96 at right angles to each other. If desired, the arms 97 and 98 may have a roller 99 at their free ends which is engaged by a moving member to supply the necessary external force for actuating the limit switch in a manner well understood by those familiar w-ith switches of the type herein described.

From the foregoing it is apparent that the resilient means including the spring 92, the pair of washers 93 and 94, the pair of ball retainers 90 and 91 and the balls 95 reacting on the sloping surfaces of the cam members 84 and 85 will constantly urge the shaft 80 and the external operator 83 to either of two positions. Also that the'shaft Si) will move with a snap action to either position after an external force which caused rotation of the shaft 80 more than half way from one position to the final desired position is removed. When operator arm 83 is positioned as shown `in FIG. l, the cam surface 85x is extended and the Acam surface 84x is retracted. When the operator arm 83 is rotated 90 counterclockwise to the second position the cam surface 85x will be retracted and the cam surface 84x will be extended. The cam surfaces 84x and 85x when in the extended positions, operate from opposite sides of the vertical center line at opposite ends of the cavity 70. When the cam members 34 and 85 are positioned so the cam surfaces 84x and 85x are retracted, then the surfaces 8411 and 85V will be in alignment with the upstanding wall 60 on the plunger head 55. The surfaces 84V and 85V on the cam members 84 and 85 and the inclined surface 61 and clearance surface 62 on the plunger head 55 are arranged so that when the surfaces 84v and 85v are presented toward the plunger head 55, the plungers will not be depressed by the cam membersl 84 and 85 and the switch 49 will not be actuated. However, as the shaft 80 is rotated slightly more than 45 in a direction to cause one of the cam surfaces 84x and 85x to move toward the extended position, the curved portions 84y and 85y will first engage the inclined surface 61 and cause the plunger to begin to move. Continued movement of the shaft 80 after 45 will cause one of the cam surfaces 84x and 85x to engage the inclined surface 61 to cause a constant depression of a plunger, thereby actuating the switch 49.

arrn 83 will cause the shaft 80 to rotate in either a clockwise or counterclockwise direction to actuate the cam members 84 or 85 which in turn will actuate one of the plungers 30p-33p. The limit switch according to the present invention can be made to operate in response to a clockwise movement or a counterclockwise movement of the operator 83 by properly locating the plungers 30p- 33p for the various rotative positions of the operator mechanism 24 on the top wall of the enclosure 2t). As will be described, when the operator mechanism 24 is positioned as respectively having the shaft 80 extending from the front wall 100, the left sidewall, the rear wall and the right sidewall, various modes of switching operations may be obtained. In the following description, clockwise and counterclockwise refers to the operation obtained when viewing-the end of the 'shaft 80. Further it will beseen that if the limit switch is to properly respond to rotation of the shaft 80, at least one plunger must be removed, as only one of the plungers at one of the corners of one diagonal will be active. If desired, the other two plungers at the opposite corners of the other diagonal may be included, even though they will act as spares. This result is obtained because the surfaces 84x and 85x do not engage the plungers which act as spares.

It is believed the following tabulation will illustrate the foregoing, wherein CW refers to clockwise rotation of the shaft 80, CCW refers to counterclockwise rotation at the various positions of the operating mechanism 24 on the housing. Further, CW (Maintained) indicates the actuator 50 of the switch 49 is depressed when the operator 83 is in the clockwise position and is released when the operator 83 is in the counterclockwise position. Similarly, CCW (Maintained) indicates the actuator 50 is depressed when the operator 83 is in the counter clockwise position and released when the operator 83 is in the clockwise position.

The external operator mechanism 24 is securable to the .top surface of housing in any of the positions indicated when screws are passed through the openings 75 at the opposite corners of the housing 66 are tightened in the threaded bores 39 of the bosses 38. It is apparent that when the external operator mechanism 24 is in position on the housing 20, relative rotation of the housing 66 of the external operator mechanism 24 and the housing 20 is effectively prevented by the bosses 38 which are received in the recesses 68 without depending on the screws to prevent rotation of the parts. Further, a gasket seal which is pressed into sealing engagement between the housing 66 and the housing 20 when the external operator mechanism 24 is applied to the housing 20 effectively prevents entrance of foreign matter into the cavity 34.

While certain preferred embodiments of the invention have been specifically disclosed, it is understood that the invention is not limited thereto, as many variations will be readily apparent to those skilled in the art and the invention is to be given the broadest possible interpretation within the terms of the following claims.

What is claimed is:

1. An operator for an electric limit switch having the switch within an enclosure and a movable plunger extending from an end of the enclosure, said operator comprising; a housing mountable in any one of a plurality of ani gular positions on the end of the enclosure, said housing p when mounted on the enclosure having a cavity facing said end and a pair of spaced axially aligned bores extending from opposite walls of said cavity in an axis parallel to said end, a rotatable shaft journalled in said bores having a portion disposed in the cavity and an end extending through one of the bores external to the housing, a pair of identical members nonrotatably mounted in spaced relation on the portion of the shaft in said cavity to have like faces on said members facing in opposite directions,- stop means on each of said members engageable with a portion of the housing for preventing rotation of each member in one direction of rotation beyond a predetermined position, a camming surface on each member arranged to engage a camming surface on an end of the movable plunger and a resilient means including a portion of each member arranged to resiliently maintain at least one of said members in said predetermined position.

2. An operator for an electric limit switch having the switch within an enclosure and a movable plunger extending frorn an end of the enclosure, said operator comprising; a housing mountable in any one of a plurality of angular positions on the end of the enclosure, said housing when mounted on the enclosure having a cavity facing said end and a pair of spaced axiallyaligned bores extending from opposite walls of said cavity in an axis parallel to said end, a rotatable shaft journalled in said bores having a portion disposed in the cavity and an end extending ex-- ternal to the housing, a pair of identical members nonrotatably mounted in spaced relation on the portion of the shaft in said cavity to have like faces on said members facing in opposite directions, each of said members having a pair of stop means with each stop means being engageable with a portion of the housing for limiting rotation of each member between two predetermined positions and a camming surface on each lmember arranged to engage a camming surface on an end of the movable plunger and a resilient means including a portion of each member arranged to resiliently maintain said members in said predetermined positions.

3. An operator for an electric limit switch having the switch within an enclosure and a movable plunger extending from an end of the enclosure, said operator comprising; a housing mountable in any one, of a plurality of angular positions on the end of the-enclosure, said housing when mounted on the enclosure having a cavity facing said end and a pair of spaced axially aligned bores extending from opposite walls of said cavity in an axis parallel to Said end, a rotatable shaft journalled in said bores having a portion disposed in the cavity a-nd an end extending through one of the bores external to the housing, a pair of identical members nonrotatably mounted in spaced relation on the portion of the shaft in said cavity to have like faces on said members facing in opposite directions, each of said members having a pair of stop surfaces on its periphery which are engageable with a portion of the housing for limiting rotation of each member between two predetermined positions, a camming surface on each member arranged to engage a camming surface on an end of the movable plunger and a resilient means including a portion of each. member arranged to resiliently maintain said members in said predetermined positions.

4. An operator for an electric limit switch having the switch within an enclosure and a pair of movable plungers extending from an end of the enclosure, said opera tor comprising; a housing mountable on the end of the enclosure, said housing when mounted on the enclosure iaving a cavity facing said end and a pair of spaced axially aligned bores extending from opposite wallsI of said cavity in an axis parallel to said end, a rotatable shaft journalled in said bores having a portion disposed in the cavity and an end extending through one of the bores external to the housing, a pair of identical members nonrotatably mounted in spaced relation on the portion of the shaft in said cavity to have like camming faces on said members facing in opposite directions, stop means on a rst peripheral portion of each of said members engageable with a portion of the housing for preventing rotation of each member in one direction of rotation beyond a predetermined position, a camming surface on a second peripheral portion of each member arranged to engage a cam mining surface on an end of one of the movable plungers and a resilient means including a spring surrounding the shaft and positioned between the camming faces of the members to resiliently maintain at least one of said members in said predetermined position.

5. An operator for an electric limit switch having the switch within an enclosure and a movable plunger extending from an end of the enclosure, said operator comprising; a housing mountable on the end of the enclosure, said housing when mounted on the enclosure having a cavity. facing said end and a pair of spaced axially aligned bores extending from opposite walls of said cavity in an axis parallel to said end, a rotatable shaft journalled in said bores having a portion disposed in the cavity and an end extending through one of the bores external to the housing, a pair of identical members nonrotatably mounted in spacedrelation on the portion of the shaft in said cavity to have like faces on said members facing in opposite directions, each of said members having a pair of stop surfaces disposed at right angles to each other on the periphery of each member with each of said surfaces being engageable with a portion of the housing for limiting rotation of the members in opposite directions of rotation beyond two predetermined positions and a camming surface on each member arranged to engage a camming surface on an end of the movable plunger and a resilient means including a surface portion of each member and a spring surrounding the shaft and positioned between the members arranged to resiliently maintain said members in said predetermined positions.

6. The combination recited in claim 5 wherein the surface portion of each member is formed to have inclined surfaces which extend in opposite directions from a ridge.

7. The combination as recited in claim 6 wherein a pair of balls biased by the spring into engagement with the inclined surfaces causes the member to move to the predetermined position after the balls have moved over the ridge during movment between the inclined surfaces.

8. The combination as recited in claim 5 wherein a pair of plungers extend from the end of the enclosure and the camming surface of one of the members engages the camming surface of one of the pair of plungers for moving the said one plunger when the members are moved in one direction of rotation and the camming surface of the other of said members engages the camming surface ofthe other of the pair of plungers for moving the said other plunger when the members are moved in a direction opposite the said one direction of rotation.

References Cited by the Examiner UNITED STATES PATENTS 2,423,361 7/ 1947 Wood. 2,766,772 10/1956 Welty et al 74-107 X FOREIGN PATENTS 1,208,507 9/1959 France.

972,996 11/ 1959 Germany.

OTHER REFERENCES German printed application No. DAS 1,102,881, published Mar. 23, 1961.

MILTON KAUFMAN, Primary Examiner.

BROUGHTON G. DURHAM, Examiner.

D. H. THIEL, Assistant Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE 0F CORRECTION Patent No. 3,257,856 June 28, 1966 Thomas Parris, Jr.

It is hereby Certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as Corrected below.

In the drawings, sheet l, FIG. 2, for the reference Character "84" read 85 for the reference Character "85" read 84 g and same sheet l FIG. 3, for the reference Character "87" read 88 and for the reference Character "88" read 87 sheet 2, FIG. 6, for the reference character "61" read 62 and for the reference character "62" read 6l column 3, line 2U, strike out "quadrate"; column 4 line 3l for "have" read has Column 7, line 64, for "8St" read 85s same line 64, for "87" read 88 Column 8, line 17, for "85s" read 85t line 18, for "87" read 88 line Zl0, for "84t" read 84s line L11, for "88" read 87 Column 9, line 73, for "are" read and Signed and sealed this 5th day of September 1967 (SEAL) Attest:

ERNEST W. SWIDER EDWARD J BRENNER Attesting Officer Commissioner of Patents 

1. AN OPERATOR FOR AN ELECTRIC LIMIT SWITCH HAVING THE SWITCH WITHIN AN ENCLOSURE AND A MOVABLE PLUNGER EXTENDING FROM AN END OF THE ENCLOSURE, SAID OPERATOR COMPRIS ING; A HOUSING MOUNTABLE IN ANY ONE OF A PLURALITY OF ANGULAR POSITIONS ON THE END OF THE ENCLOSURE, SAID HOUSING WHEN MOUNTED ON THE ENCLOSURE HAVING A CAVITY FACING SAID END AND A PAIR OF SPACED AXIALLY ALIGNED BORES EXTENDING FROM OPPOSITE WALLS OF SAID CAVITY IN AN AXIS PARALLEL TO SAID END, A ROTATABLE SHAFT JOURNALLED IN SAID BORES HAVING A PORTION DISPOSED IN THE CAVITY AND AN END EXTENDING THROUGH ONE OF THE BORES EXTERNAL TO THE HOUSING, A PAIR OF IDENTICAL MEMBERS NONROTATABLY MOUNTED IN SPACED RELATION ON THE PORTION OF THE SHAFT IN SAID CAVITY TO HAVE LIKE FACES ON SAID MEMBERS FACING IN OPPOSITE DIRECTIONS, STOP MEANS ON EACH OF SAID MEMBERS ENGAGEABLE WITH A PORTION OF THE HOUSING FOR PREVENTING ROTATION OF EACH MEMBER IN ONE DIRECTION OF ROTATION BEYOND A PREDETERMINED POSITION, A CAMMING SURFACE ON EACH MEMBER ARRANGED TO ENGAGE A CAMMING SURFACE ON AN END OF THE MOVABLE PLUNGER AND A RESILIENT MEANS INCLUDING A PORTION OF EACH MEMBER ARRANGED TO RESILIENTLY MAINTAIN AT LEAST ONE OF SAID MEMBERS IN SAID PREDETERMINED POSITION. 